DESCRIPTION: The objective of this proposal is to continue studies of the neurobehavioral development of children with early hydrocephalus. The project began in 1988, when a longitudinal study of children 5-7 years of age (N = 125) with hydrocephalus due to four different etiologies and contrast groups of children from the same etiology groups but no hydrocephalus was established. The study was expanded in 1991 by the recruitment of a large cohort of children 6-14 years of age from the same etiology groups with shunted, arrested, or no hydrocephalus (N=211). Both cohorts have received extensive evaluations of cognitive and motor skills, family and sociodemographic variables, and magnetic resonance imaging (MRI) of the brain. quantitative and approaches to the analysis of the MRI data have been developed and implemented. For this competing continuation, five new studies are proposed under four specific aims using cross-sectional (Studies A-E) and longitudinal (Studies D-E) designs, along with the continuation of studies based on MRI morphometry: (1) CNS lesions and cognitive development: Implementation of Methods for cortical parcellation across the entire brain for the cross-sectional cohort will be implemented. This will permit more specific analyses of the relationship of CNS changes in children with hydrocephalus and comparison groups in relation to cognitive skills. Study A, experimental investigations of interhemispheric transmission and hemispheric specialization are proposed to further clarify the role of the corpus callosum defects characteristic of children with hydrocephalus. (2) Nature of impaired abilities: Children with spina bifida show problems with mastery motivation, social mastery, and executive functions. Study B will used observational methods to study these skills in children with hydrocephalus in relation to other executive function measures and to the MRI morphometry measures. Study C will involve expanded studies of language discourse, form, and content to determine whether the language deficiencies of children with hydrocephalus are related to the integrity of the rostrum and anterior regions of the brain. (3) Academic achievement: Study D will involve a cross-sectional comparison and a follow-up of the longitudinal cohort to address the development of reading comprehension, academic skills, and related cognitive skills into adolescence. (4) Behavioral development. Study E will involve further behavioral ratings and a structured interview as part of the follow-up of the longitudinal cohort, to determine whether the rate of behavior disorders increases as children with hydrocephalus move into adolescence.